Precipitation over the last few days in Italy has reduced the deficit of the Snow Water Equivalent, the water contained in the snow, which provides an indicator of the water available for the spring and summer months. The situation has improved especially in the Alps, while the deficit remains pronounced in the Apennines
March has opened with rain and, at higher altitudes, with snow. After months in which, as we have reported, the monitoring by CIMA Research Foundation detected a serious snow deficit (or, more precisely, a deficit of water contained in the snow, the Snow Water Equivalent or SWE), this undoubtedly appears as good news from the perspective of water resources. But can we say that we have mitigated drought in view of the spring and summer months? Let’s give a more precise picture of the situation, based on the data we have collected and analyzed in recent days.
In mid-February, we defined the situation in Italy as worsening compared to the end of 2023 and the beginning of 2024, with an SWE deficit of -64%. Today, however, we estimate a deficit of -29%: a significant recovery, but still indicating a scarcity of snow compared to the last decade.
This picture regards the situation at the national level. However, at the local level, the picture is more varied: the best conditions are in the Alpine region, where the deficit is -21%, and worse for the Apennines, where the deficit is -78% (the value refers to Abruzzo, which represents a representative index for the central Apennine area). The relatively good situation in the Alps can be attributed to the abundant precipitation that, in February, affected the northern part of the peninsula. Instead, the central-southern regions remained “dry,” with virtually no snow cover on the Apennines, except for higher altitudes.
“It is definitely a more positive situation compared to the past few months, and also compared to last year, and it has brought an improvement for the alpine rivers as well. For the Po, Italy’s most important snow-water reservoir, the deficit is now -11%, in the range of what can be considered normal interannual variability at this time of the season,” comments Francesco Avanzi, researcher at CIMA Research Foundation. “Furthermore, the deficit, although still present, is less pronounced at higher altitudes, from where the ‘water supply’ comes during summer.”
“However, this positive situation must be read bearing in mind an important consideration, namely that February was indeed a very wet month. But it was also a very warm month,” Dr Avanzi continues. In fact, explains the researcher, the winter of 2023-2024 recorded significant temperature anomalies, which in Northern Italy reached peaks of up to +3.5°C compared to the last decade. This implies that the snow that managed to accumulate could also be subject to early melting.
So, what should we expect for the coming months? Can we already predict how the situation will evolve? “Actually, with the arrival of spring, we enter a transition period during which new snowfalls may occur (starting already from this second weekend of March). Historically, in Italy, the peak of snow accumulation occurs in early/mid March. However, these latter periods of snowfall overlap with periods of melting,” says Dr Avanzi. “Estimations thus become more complicated. It is necessary to continue monitoring the situation carefully, also because we know that drought is a slow phenomenon to develop over time, and local conditions are not always representative of the rest of the country.”